Actuating mechanism for sensitive horizon bars



Oct. 10, 1950 J. s. ADKINS 2,524,745

ACTUATING MECHANISM FOR SENSITIVE HORIZON ms Filed March 21, 1949 191/5 0/" earae Patented Oct. 10, 1950 ACTUATING MECHANISM FOR SENSITIVE HORIZON BARS John's. Adkins, Dayton, Ohio Application March 21, 1949, Serial No. 82,673

6 Claims. (01. 33-204) (Granted under the act-of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described herein maybe manufactured and used by or for the United States Government for governmental purposes without payment tome of any royalty thereon.

This invention relates to improvements in aircraft flight attitude indicating instruments and more particularly to actuating mechanisms for shifting the horizon indicating barsof vertical gyro indicators, having for an object the provision of improved actuating means for increasing the sensitivity of the horizon indicating bar of a vertical gyro indicator or artificial horizon.

Another object of this invention is the provision of improved horizon bar actuating means which permits maximum freedom of movement of the actuating gimbal means for the bar, and is extremely sensitive throughout the range of movement of the bar, particularly at or near the level or zero indicating position of the bar.

A further object is the provision of a horizon bar actuating mechanism which is extremely sensitive and accurate throughout the range of movement of the bar, particularly at or near the zero indicating position, having improved interengaging actuating means between the bar and the actuating gyroscope casing or rotor bearing member for positively coordinating the movement and position of the horizon indicating bar throughout the complete relative tilting movements of the actuatinggyroscope casing and gimbal without obstructing or materially resisting its tilting movements.

Other objects and advantages of the invention will become apparent from the following descriptions, taken in connection with the accompanying drawings, in which like reference characters refer Y to like parts'in the several figures.

Fig. 1 is a side elevation of an artificial horizon indicating gyroscopic instrument, incorporating my improved horizon bar actuating mechanism, parts of the casing and the supporting structure being broken away and shown in section.

Fig. 2 is a detailed perspective view of the horizon bar member and the cam and pin actuating means therefor, illustrating the partsv somewhat diagrammatically, in their relative positions when the horizon bar is in its level or zero position.

Fig. 3 is a side elevation of the horizon indicating bar means and the cam and pin actuating means therefor, diagrammatically illustrating the relative position of the cam and pin when the horizon bar is shifted to one end of its range of movement by the pin, which is shown in dotted lines, when the cam has been rotated in the direction of the arrow to the position where the move- 2 ment of the bar by the pin is discontinued and the relative cooperative engagement between the bar member 14 and the periphery of the cam means is established, the dotted lines illustrating the positionof the pm just as it disengages the horizon bar slotted structure, and the full lines illustrating a further relative rotative movement ofthe cam member and pin while the bar member in cooperative controlled engagement with the periphery of the cam member and is positioned by the cam member.

Fig. 4 is a view similar to Fig. 3, but showing the horizon indicating bar and the actuating cam member in full lines, after the cam and pinhave been rotated relative to the case, throughout a sufficient angular distance in the direction of the arrow to shift the horizon bar to the other end of its range of movement, the full lines showing the bar while under the control of the periphery of the cam while the dotted linesshow the pin shifted to the position where the bar actuation by the pin begins and the actuation of the bar member by the cam is interrupted.

Fig. 5 is a detail vertical sectional view taken approximately on the plane indicated by the line 5. 5 in Fig. 2. 1

ventional design having a transparent frontwindow 3 through which 7 the horizon indicating bar member 4 is observed, bank angle indicating indicia (not shown), being inscribed on the flange 5, an adjustable fore-and-aft or horizon reference member for the aircraft, being indicated at 6, preferably in the form of a miniature airplane which is adjustable vertically with respect to the horizontal axis of the casing I and the midposition of the horizon bar la by an adjusting knob I.

The stabilizing means or gyroscope device as shown comprises a gimbal ring 8, pivoted on suitable fore-and-aft antifriction trunnions (not shown), but of conventional construction, and arranged to tilt about the fore-and-aft axis 2, the gimbal ring 3, as shown in Fig. 1 is broken away, but extends forwardly at opposite sides of the rotor casing or hearing member 9 and in turn pivotally supports the rotor bearing member or casing 9 on a transverse axis or pivots Ill in the conventional manner so that the rotor bearing member may tilt about the pivotal axis III which intersect h IOIe-and-aft axis 2 and is transverse to the fore-and-aft axis 2. The rotor (not shown) is spun within the casing 9 on a normally vertical axis I I by any suitable conventional means such as by an electric motor, or by the to substantially the distance between the axis I and the side edge I8 which is at the greater distance from the axis II] when the horizon bar is shifted to the end of its range of movement as shown in Fig. 3 or Fig. 4. The other or smaller usual air jets. The rotor bearing member of case 9 is pendulous, or a suitable erecting means may radial distance from the axis ID to the arcuate be provided to erect the gyroscope rotor spin axis surface 24, is-equal'substantially to the distance to the true vertical in a manner well known in the from the other or closer straight edge I8 to the prior art, so that the normal vertical axis II axis Ill under the same condition. The sum of corresponds to the true vertical at'all times. the two radial distances just mentioned is slightly A spherically curved indicator plate -I2-isproless'tha'n the distance between the two straight vided, secured to an arm (not shown) projecting edges I8. from the front end of the gimbal'ring 8 'theplate The cam 2i is formed with curved contiguous having an index pointer or indicator I2a prosurfaces 25 connecting the two arcuate surfaces jecting upwardly from its'top edge to cooperate 23 and Z 'i'at'their ends, the greatest distance be- With the scale on the flange 5, to'indicate the tween these two curved connecting surfaces being degree of lateral tilt or bank of the casing I and, somewhat less than the distance between the of course, the bank angle'of the aircraft on which straight edges I8 so as to leave some play bethe horizon is mounted relative to the vertical tween the cam member 2| and the edges I8 position of the rotor'bearing casing or rotor spin throughout at least greater portion of the range axis '9,"a supporting part of the aircraft being diagrammatically indicated at I3. .Thehoi'izon bar structure, as best seen in Fig. 2-; comprises a bail-like member having laterally -spacedaside arms or-connecting parts I4 and I5 extending ,rearwardly from the indicating bar member. 4aproper,'theextremities of the side :arms lfi'and I5 being pivoted on the gimbal ring 8: rearwardly of the axis I0,iand parallel to the Qznaxis I0. xThe pivots'forithe bar are located in a plane passing through the 'fore-and aft axis 2 1-: "so that when. the horizonbar' t is in the horizontal "position its 'centerwill lie in the last mentioned planejrz'lhe' connecting member or 'arm" It is ilatrallyToiTset; as findicated at It, and is also apertured'interm'ediatethe arm 4a and the pivot pointvfor the arm to leavean enlarged o ening l'lhaving parallel guide edges lying at opposite "1-: sides of .a plane passing throughthe'pivots for the'arms' I4. and Hi and through theindicating :1 .bar member ta. In'"other words the portion It .2." oflithe: bar member 4 is provided with parallel side bars projecting:forwardly at opposite sides 2': of the'pivotal axis for the bar, the adjacent edges ofatheparallelfside b'ars being indicated at I8; I8,

the remote ends of the bars converging together towardsthahorizon indicating bar 4a at their fro'nt' ends.

'fii' lojecting'radially forward from the pivotal The horizon bar 4 4a is formed of thin, light material such as a w thin sheet" aluminum or brass stampingand it may be counterbalanced at its" rear end in the "mconventi'onal manner if desired.

r seeured to the rotor bearing member 9501i the pivotal axis In thereof, is a somewhat triangular 'shaped' actuat ng'cani' 'r'n'e'inber, indicated generally at' 2!, IiaVing a 3 peripheral channel or 'groove' llz; "The parallel spaced sidebars or edges '18 arereceivedgin, and'retained in, the channel 0:22: b'y-the'side'fianges of the channel. The cam member ZI is forn'1ed with two arcuate surfaces -23-24; having dilferent radii, their per pheries of swinging movement of the horizon bar indi- 'cato'rm'en'iber id, particularly when the cam ZI is at ornear the positions shown in Figs. 1 and 2. Located in a plane bisecting the greater arcuate surface 23 and'passing through the axis If! in parallel relation to the axis I0 is an actuator pin or slide member 26, arranged to engage the '='"sides'of 'the open ended slot 2!] when the cam 2I is in thep'ositions shown in Figs. 1 and 2, and

whnthec'asing I and 'gimbal ring 8 are tilted in the vertical plane'from the position shown, to

displace the positions of the cam 2I and slide or "-pin 26, displacing'the horizon indicator member 'to the position'shown in Fig. 3 or 4. After the "cam 2"! is relatively rotatably displaced to dispose surfaces 23 and 2 3 of thecam 2I engage the straight"edges' I8, this position being shown in Figs. Sand 4 in full lines. Continued rotation of the'case' about the axis II] (or relative rotation of the rotor bearing member 9 and the cam 2| fixed ,"thereto) will cause the larger arcuate surface 23 toengage the oppositestraight edge portion I8, "-'shi1ting the horizon bar to to the opposite end of "its range of 'rnovement, of course, shifting the "position of "the entrance end of the slot 20 so that'th'epin 26' can now enter the slot, the actuation of the horizon bar being then caused by the movement of the pin 26 in the slot 20 instead of the'mbve'me t of the cam 2|. The position of the actuating pin 2| at a remote distance from the worn axis It, so as to swing close to the pivotal axis for the horizon bar member 4 while the pin is inthe slot-{29 affords an extremely sensitive and positive adjustment of the horizon bar la throughout its complete range of movement, the

"degree of movement of the-bar being somewhat "exaggerated with respect to the degree of relative tilt of'th'rotor bearing member 9, particularly "at and adjacent to the horizontal, or zero, or

""lvel 'position'faccurately indicating the degree of tilt of the fore-and-aft axis 2 as indicated on the scale I2, throughout the entire range of movement of the'horizon bar 4a, and also permits free *re'lativerotative displacement of the rotor bearing member vertical axis I8 about either the fore- -and'-aft"axis 2 or about the lateral axis I0.

In. the operation. as the casing, or the fore-andaft axis} tilts with respect to the rotor bearing "member '9 from the position shown in Fig. 1, the pin 2ti engages the :slot 20 and swings the horizon 75*ba'r lla throughoutits range of movement to the being located in' the'base of the channel" 22. The n radialdi tance between the center of the arcuate surface 23, is greater than the radius of the other mrsurfaca both surfaces having their centers 10- wca-ted substantially at the rotary axis Ill of the Noam member, the ra'dius or the surface 23 i'sequal sides l8 of the open portion of the horizon bar,

lever arm i l to retain the horizon bar do its maximum upper (or lower) indicating position, and

relative rotation of the gimbal ring 8 and case I around the axis l0 causes the periphery of the cam member 2! to strike the opposite straight edge portion I 8 and shift the horizon bar member iii-4a to the other extreme indicating position with respect to the scale 12, the arcuatesurfaces 23, 24 retaining the lever arm [4 and its bar member 4a in this position duringthe relative rotation of the parts and until the pin 26 again enters the slot as the arcuate surfaces 23, 24 move away from the straight edge portions [8. Continued rotation of the fore-and-aft axis 2 about the transverse axis l0 brings the cam member 2! again into the position shown in Fig. l'where the pivots l [l and I5 and the slide member or pin 26 line up, with the bar 4a indicating the level position as shown.

Having shown and described a simple embodiment of my invention, it is understood that the invention is not limited to the exact details of construction disclosed herein and minor changes and modifications may be made without departing from the spirit of the invention as defined in the accompanying claims.

I claim: t

1. In an artificial horizon for aircraft, a rotor and a rotor bearing member. a gimbal ring having a transverse axis upon which said bearing mem ber is pivotally mounted, an outer casing having a fore-and-aft axis upon which the gimbal ring is pivoted, a horizon indicating bar member pivoted pivoted about a transverse axis on'the rear portion of the gimbalring, having a horizon indicating portion spaced remotely from said bar member pivot and an, intermediate connecting portion formed with an enlarged transverseopening extending therethrough, having a short camming about a transverse axis on the rear portion of the gimbal ring, having a horizon indicatingportion spaced remotely forward from the bar member pivot, having an intermediate connecting portion formed with spaced parallel side bar members extending forwardly from the bar member pivot justing means comprising a cam and pin actuator i fixed on the rotor bearing member to rotate therewith about the pivotal axis thereof, having a pin projection thereon disposed in actuating engagement with the short slot throughout a predetermined range of travel of the indicating bar member above, and below, the intermediate or zero indicating position thereof, and disengageable from the short slot upon continued rotation of the cam and pin actuator and movement of the indicator bar to the predetermined maximum range of travel thereof, said cam having a periphery engageable with the parallel side bar portions of the horizon indicating bar upon continued rotation of the cam and pin member, to determine the position of the bar member relative to the rotor bearing member while the pin is withdrawn from its engagement with the short slot by the continued rotation of the cam and pm actuator.

2. In an artificial horizon for aircraft, a rotor and a rotor bearing member, a gimbal ring having a transverse axis upon which said rotor bearing member is pivotally mounted, an outer casing having a fore-and-aftaxis upon which the gimbal ring is pivoted, a horizon indicating bar member slot extending from the opening toward the bar member pivot, horizon indicator bar member actuating means fixed on the rotor bearing member to rotate therewith relative to the casing about the pivotal axis of the rotor bearing member, en gageable with the short camming slot throughout a'predetermined indicating range of swinging movement of the horizon indicating member and ber and the position of the short slot relative to the pivotal axis of the gimbal ring throughout the range of relative rotative movement of the bearing member with respect to the gimbal ring.

3. In an artificial horizon for aircraft, a rotor and a rotor bearing member, a gimbal ring having a transverse axis with which said rotor bearing member is pivotally mounted, an outer casing having a fore-and-aft axis upon which the gimbal ring is pivoted, a horizon indicating bar member pivoted about a transverse axis on the rear portion of the gimbal ring, having a horizon indicating portion spaced remotely forward from the bar member pivot with an intermediate connecting portion formed with an enlarged transverse opening therethrough having spaced side edges extending in parallel planes at opposite sides of the bar member and transverse to the pivotal axis of the bar member, said horizon bar member connecting portion having a lateral offset portion 7 formed with an open slot communicating with said opening and extending radially toward the bar member pivot in an offset plane parallel to the opposite edges of the enlarged opening, ro-

tary bar actuating means fixedly carried by the rotor bearing member to rotate therewith, comprising a somewhat triangular shaped cam member having arcuate peripheries of predetermined different radii located at diametrically opposite sides of t e pivotal axis of the rotor bearing member, the combined radii of the arcuate surfaces being equal to substantially the distance between the parallel edges of the opening with the greater radius equal to substantially the distance between the rotor bearing member pivot and the side of the said transverse opening most remote from the bearing member pivot when the horizon indicating bar member is rotated on its pivot to an extreme indicating position limit at the end of its range of movement, while the radius of the other arcuate surface is equal to the distance between the bearing member pivot and the opposite or nearest parallel side of the opening, said cam member being disposed within the opening in the bar member connecting portion in the path of movement of the bar members, to actuate the bar member, and a pin member projecting laterally from the cam member into the plane of movement .of the laterally offset portion, to enter the open slot, engageable with the side walls of the slot, to actuate the horizon bar member while the arcuate surfaces of the cam member are out of engagement with the spaced parallel edges of the opening in the intermediate connecting portion of the horizon bar member. 4

l. ln an artificial horizon for aircraft, a rotor and a rotor bearing case, agimbal ring having :a transverse axis-upon which said rotor bearing case is pivotally mounted, an outercasing having a fore-and-aft axisupon Which'the gimbal ring is pivoted, a horizonindicating bar member pivoted about a transverse axis on'the'iea'r' portion member through a predetermined exaggerated angle at a rate proportional to the rate at ,which the rotor bearing Qcase tilts, said slide mov- .able out of. theslotlto disengage the horizon bar member at angles of tilt thereof greater than said predetermined angle,.and va disc shaped actu-' ator member upon whichsaid slideis fixed, se-

cured ,to the bearing .case tourotate therewith about the bearing case pivot, having ofiseteam- ,ming surfaces thereon movable into actuating engagement with the parallelside edges" of the opening for holding the horizon. bar member in its ,maximum shifted/positions, andshifting the bar member relative .toi therrotor hearing case -wh enrthe slideisdisengaged from the slot and the rotorbearing case rotatesrabout itspivot beyond a predetermineddegree.

5. Apparatus asclaimed in c1aim.4 ,in. which ,the disc-shaped actuator member is formediwith a peripheralgroove .to..rec,eive the paralleluside I Number 8 edges ofthe horizon bar member therein, and is formed with arcuate' camrning surfaces in the:

base of the peripheral groove which are engage.-- able with the parallelside edges of the horizon. bar member when the slide is disengaged from; the slot, to hold thelhorizon bar member in a, predetermined adjusted position, and position the,- entrance of the short slot for subsequent engage- 'ment with the slide incident to subsequent rela-- tive rotative movement between the gimbal ring; and the rotor bearing case.

6. Apparatus as claim d in claim 5 in which the arcuate surfaces are disposed at opposite sides of the pivotal center of the rotor bearing;

case with their radial centers at the pivotal cen- ,ter,,having radial distances from their pivotal centers to the arcuafte surface equal substantiallytothe distance between the spaced parallel side edges, one of the radial distances being greater thanthe other, and equal respectively to the distance between thev bearing casepivot and theparallel side edge of the opening through thehorizon bar member when the bar member is: shifted to its maximum deflected indicating position, withthe slide disengaged from the slot.

JOHN S. ADKINS.

REFERENCES CITED The following references record in thefile of thispatent:

UNITED STATES PATENTS Name I vDate 1,982,636 Carlson Dec; 4, 1934 2,207,414 Rodanet July 9, 1940 2,326,835 Carter Aug. 17, 1943 2,467,254 Carlson 'Apr. 12, 1949 2,485,552. Aumuller Oct. 25, 1949 

